She remembers the look in his eyes when he watched her painting that day. The mug shattering into pieces on the concrete floor, the sudden certainty that she was talking to a total stranger. Stretch trotting away in fear. ‘My best friend Bex, she thinks I might have something called Capgras delusion.’

Ajay looks up at her, cocking his head to one side.

‘Capgras? Interesting. It’s a rare condition.’

‘But you have heard of it?’ she asks, noting that he pronounces it with a silent ‘s’. It suddenly all feels a little too real, hearing the word repeated by a leading neuropsychiatrist.

‘Of course,’ he says. ‘Technically it’s classified as a delusional misidentification syndrome – an extremely unusual disorder.’ He pauses, looking at her again with a certain detachment, what she’s come to recognise as clinical interest. Maybe it’s not such a long shot after all. ‘It’s more common in women than men,’ he adds. ‘And it can occur in association with migraines.’

She stares at him. They both know she suffered from migraines after the accident.

‘And is it true you only think someone’s a double when you see them?’ she asks. ‘Not when you talk to them on the phone.’

‘That’s correct – connectivity between the auditory cortex and memory appears to be unaffected. In fact, auditory cues can be used to help patients restore the association between a person and a face.’ He pauses. ‘But there’s a lot we still don’t understand about Capgras. And at present there’s no known cure. In some cases, when it’s caused, say, by a right hemisphere lesion, only the left visual field is affected.’

‘Meaning?’ she asks, her head beginning to spin. Only the left visual field is affected.

‘You only think the person is a double if they’re to your left.’

Her eyes start to well up.

‘As I say, it’s a rare condition,’ Ajay repeats, noticing her discomfort. ‘Very rare.’

She doesn’t know whether to be pleased or frightened. The thought of no cure for Capgras isn’t great. Nor is the prospect of seeing Rob as a double for the rest of her life. But at least it might explain what’s been happening to her. Her own brain injuries from the accident were all on the right hemisphere, which controls the left part of her body, including her left eye. Does she only think Rob is a double when he’s in her left field of vision? When she dropped the mug of tea on Saturday morning, he was on her left. And at Truro station, when the woman approached Rob… he was to Kate’s left too.

63

Silas